ABSTRACT
Introduction: Team sport athletes have increased susceptibility to upper respiratory symptoms (URS) during periods of intensified training and competition. Reactivation of Epstein-Barr Virus (EBV) may be a novel marker for risk of upper respiratory illness (URI) in professional athletes. Aims: To investigate changes in salivary EBV DNA (in addition to the well-established marker, salivary secretory immunoglobulin A), and incidence of URS in professional footballers. Methods: Over a 16-week period (August to November 2016), 15 male players from a professional English football League 1 club provided weekly unstimulated saliva samples (after a rest day) and recorded URS. Saliva samples were analyzed for secretory IgA (ELISA) and EBV DNA (qPCR). Results: Whole squad median (interquartile range) saliva IgA concentration and secretion rate significantly decreased (p < .05) between weeks 8 and 12 (concentration, 107 (76-150) mg/L healthy baseline to 51 (31-80) mg/L at week 12; secretion rate 51 (30-78) µg/min healthy baseline to 22 (18-43) µg/min at week 12). Two players reported URS episodes during week 10, both after IgA secretion rate decreased below 40% of the individual's healthy baseline. EBV DNA was detected in the weeks before URS but also at other times and in healthy players (overall frequency 40%, range 11-78%) and frequency was similar between the URS and healthy group. Conclusion: These findings confirm salivary IgA as a useful marker of URS risk but EBV DNA was not. Further research capturing a greater number of URS episodes is required, however, to fully determine the utility of this marker.
Subject(s)
Epstein-Barr Virus Infections , Soccer , Humans , Male , Herpesvirus 4, Human/genetics , Immunoglobulin A, Secretory/analysis , Saliva/chemistry , BiomarkersABSTRACT
Upper respiratory tract infection (URTI) can compromise athlete preparation and performance, so countermeasures are desirable. The aim of this study was to assess the effects of ColdZyme® Mouth Spray (ColdZyme) on self-reported upper respiratory tract infection in competitive endurance athletes under free-living conditions. One hundred and twenty-three endurance-trained, competitive athletes (recruited across 4 sites in England, UK) were randomised to control (no treatment, n = 61) or ColdZyme (n = 62) for a 3-month study period (between December 2017 and March 2018; or December 2018 and April 2019). They recorded daily training and illness symptoms (Jackson common cold questionnaire) during the study period. A total of 130 illness episodes were reported during the study with no difference in incidence between groups (episodes per person: 1.1 ± 0.9 Control, 1.0 ± 0.8 ColdZyme, P = 0.290). Episode duration was significantly shorter in ColdZyme compared to Control: Control 10.4 ± 8.5 days vs. ColdZyme 7.7 ± 4.0 days, P = 0.016). Further analysis to compare episodes with poor vs. good compliance with ColdZyme instructions for use (IFU) within the ColdZyme group showed a greater reduction in duration of URTI when compliance was good (9.3 ± 4.5 days in ColdZyme poor IFU compliance vs. 6.9 ± 3.5 days in ColdZyme good IFU compliance, P = 0.040). ColdZyme may be an effective countermeasure to reduce URTI duration, which was significantly lower (by 26-34%) in the ColdZyme treatment group (with no influence on incidence). This may have implications for athlete performance.
